Circuit interrupters utilizing a gasevolving material as an arc extinguishing agent



3,138,683 EVOLVING ISHING AGENT 1961 June 23, 1964 D. BERG ETAL CIRCUIT INTERRUPTERS UTILIZING A GA MATERIAL AS AN ARC EXTINGU Filed March 30.

ATTORNEY United States Patent O 3,138,683 CIRCUIT INTERRUPTERS UTILIZING A GAS- EVOLVING MATERIAL AS AN ARC EXTIN- GUISHING AGENT Daniel Berg, Churchill Borough, and Charles W. Lewis, Elkins Park, Pa., assignors to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Filed Nlar. 30, 1961, Ser. No. 99,421 7 Claims. (Cl. 200-120) This invention relates to circuit interrupters, in general and, more particularly, to circuit interrupters, including fusible interrupting devices, employing a novel gas-evolving material, which evolves arc-extinguishing gases in the presence of an arc.

A general object of the present invention is to provide an improved circuit-interrupting device utilizing a novel gas-evolving material as the arc-extinguishing agent.

Still a further object of the present invention is to provide an improved circuit-interrupting device utilizing a diazonium hexafluorophosphate and derivates thereof as the arc-interrupting agent.

Still a further object of the invention is to utilize a halogenated diazonium hexailuoroph'osphate as the gas,- evolving material for effecting arc extinction in circuitinterrupting devices, such as circuit breakers, fuses, lightning arresters, etc.

A particularly desirable gas-evolving material is monochlorobenzene diazonium hexaiiuorophosphate having the chemical formula:

and particularly, the parachloro compound.

It is to be clearly understood that the term circuit interrupter not only includes conventional-type devices utilizing separable contacts, between which an arc may be drawn, but also the term is employed herein to encompass fusible interrupting devices, wherein an arc is established by the fusing of a fusible element, lightning arresters, etc. in which an established arc is to be extinguished.

Still a further object of Ithe present invention is to provide an improved circuit-interrupting device in which compressed cakes of a `novel arc-extinguishing material may be employed. Preferably such cakes collectively align to form a bore, through which the arc may be established and may evolve gases therein from said material.

Further objects and advantages of the invention will readily become apparent upon reading the following specification, taken in conjunction with the drawings, in which:

FIG. 1 is a longitudinal sectional view taken through a simplified type of circuit-interrupting device embodying the novel arc-extinguishing material of the present invention with the contact structure being illustrated in the partially open-circuit position;

FIG. 2 illustrates a longitudinal sectional view taken through a fusible interrupting device embodying the novel arcaextinguishing material of the present invention, the fuse element being shown in its intact condition; and,

FIG. 3 is a graph showing a comparison between the interrupting results of Phosfluorogen-A with boric acid and fiber.

Referring to the drawings, and more particularly to FIG. 1 thereof, the reference numeral 1 generally desig- ICC nates a circuitdnterrupting device, including a relatively stationary contact 2 and a movable Contact 3 separable therefrom to establish an arc 4, Preferably, the relatively stationary contact 2 is maintained in a iixed position within an outer enclosure 5 by means of a suitable insulating stopper 6. Suitable means, not shown, are effective to move the movable contact 3 toward the right, as viewed in FIG. 1, effecting thereby contact separation and consequent arc establishment.

Disposed within the outer insulating casing 5 is a body 7 comprising the novel arc-extinguishing material of the present invention, which body evolves an arcextinguisbing gas upon arc establishment. In accordance with the present invention, this gas-evolving arc-extinguishing material is a benzene diazonium hexailuorophosphate hereinafter referred to as fluorinated compound. Preferably a halogenated benzene diazonium hexailuorophosphate is used, such as monochlorobenzene diazonium hexaflucrophosphate having the structural formula:

This material is made by Ithe Ozark-Mahoning Company and is sold under the trade name Phosiiuorogen-A. This compound is a solid and may be applied as a layer or compressed disk, with or without a binder such as a resin.

During arc establishment, the heat generated by the arc 4 `evolves gas from the fluorinated compound at about 150 C., in accordance with the following reaction (gas) -l- N2 (gas) -l- PF5 (gas) All of the gaseous components -so evolved are good deionizing media. The reaction wherein the solid decomposes leads to a large increase in gas pressure because from one solid molecule, three gas molecules have been made. The combination of increased pressure and the deionizing properties of the gases serves to help extinguish any arc present.

As indicated above, the phosphorus pentafluoride (P135) gas in combination with nitrogen gas (N2) and P- chlorouorobenzene gas is highly effective in effecting arc extinguishment.

Examples of suitable binders for the fluorinated compound are the liquid or plastic acrylates and methacrylates and esters thereof, such as low molecular weight n-butyl methacrylate a material sold under the trade name of Lucite-44, by the E. I. du Pont de Nemours & Company. Utilizing such a binder, the material may be compressed into cake form and readily used in such state. Suitable proportions by weight, which have been found highly effective, are by weight of the iluorinated compound and 15% by weight of n-butyl methacrylate.

extinction. Mixtures of two or more compounds may be as fiber.

where R represents an organic radical such as phenyl and substituted phenyl radicals, decompose to R-F and N2 and PF5. The chlorinated benzene diazonium hexafluorophosphates are particularly useful. The suitability of a particular compound for arc interruption depends upon the Atemperature at which this would occur and the final products.

Particular examples are:

Cl- -Cl 1,3,5-trchloro-6-azohexafluorophospho-benzene, having the preceding chemical formula decomposes at about 250 C.,

2,5 dichloro-6-azohexafluorophospho-benzene, having the preceding chemical formula, and

3,4 dichloro-6-azohexailuorophospho-benzene, having the preceding chemical formula, both of the last two examples decomposing at about 200 C. 50

Other halogens such as bromine may be substituted for the chlorine. Also benzene diazonium hexafluorophosphate can be employed. All of these will likewise lead to the formation of P135 and N2 which will assist in arc used.

In summary, all solid diazonium hexafluorophosphates p will thermally decompose at various temperatures. They will all release N2 and P135 giving desirable arc-extinguishing action.

With reference to FIG. 2 of the drawings, there is shown illustrated a fusible interrupting device generally designated by the reference numeral 8. Generally, the fusible interrupting device 8 includes an outer tubular enclosure 9 formed of a suitable insulating material, such Movable longitudinally within the enclosure 9 is a metallic rod 10, to which a fusible element 11 is secured at one end thereof. The other end of the fuse wire`11 is ixedly secured to an outer metallic ferrule 12 by a terminal screw 12a. A fuse terminal 13 is secured 70 Aby a bolt 13a to the ferrule sleeve 12.

16, secured to and movable with the fuse rod 10. A 75 d manual support or handle 17 may be aixed to the outer end of the movable fuse rod` 10 to effect, at times, rightward movement thereof, against the opposition afforded by the compression spring 14, for renewal of the fuse wire 11.

Disposed within the outer insulating casing 9 is a metallic guide tube 18 and a rear electrode 19. Adjacent the right-hand end of the insulating fuse tube 9 is an inner fuse liner 20 composed of a suitable insulating material, such as ber. Positioned inten'orly within the fuse liner 20 are a plurality of superimposed pressed apertured blocks 21 Vof the Phosuorogen-A and Limite-44 (nbutyl methacrylate) the proportions, by weight, having previously been described.

When an excessive current flows between the fuse terminal 13 and the cooperable fuse terminal 22 the fuse wire 11 will fuse, and the spring action of compression spring 14 will effect the rupture and lengthening of the established arc. The heat generated by the arc Will evolve phosphorous pentalluoride (P), nitrogen gas (N2), and p-chlorofluorobenzene from the Phosuorogen-A, as previously described. The resultant evolved gases will quickly effect arc extinction by expulsion action out of the right-hand open end 23 of the tubular fusible device 8.

The interrupting device 8 of FIG. 2 may be utilized as a fuse-testing apparatus. In other words, the Phosfluorogen-A blocks 21 maybe replaced by boric acid and ber for comparison purposes. With the fuse bore 1A inch and 4 inches long, the different interruption characteristics for the test fuse with different gas-generating liners may be graphically set forth, as in FIG. 3.

FIG. 3 illustrates a comparison of the arc-interrupting properties of the instant gas-evolving material Phosuorogen-A with boric acid and ber. It will be noted that the performance of the Phosfluorogen-A is extremely effectiveY over a considerable current range A having pronounced interrupting effect within this region.

From the foregoing description it will be apparent that there has been illustrated and described a novel arc-extinguishing gas-evolving material, which is highly effective in effecting arc extinction. The gas-evolving material of the present invention may be compressed into cake form, and arranged in alignment to form an arcing bore for surrounding a considerable length of the established arc, as indicated in FIG. 2 of the drawings.

Although there has been illustrated and described particular circuit-interrupting devices including fuse structures, it is to be clearly understood that the same were .merelyl for the purpose of illustration, and that changes Vnium hexauorophosphate gas-evolving material disposed adjacent said arc to effect the extinction thereof.

3. A circuit-interrupting device including means for establishing an arc, and a solid phenyl diazonium hexafluorophosphate gas-evolving material disposed adjacent said arc to effect the extinction thereof.

V4. A circuit-interrupting device including means for establishing an arc, and a monochlorobenzene diazonium hexauorophosphate gas-evolving material disposed adja- 7. A fusible electrical device including a fusible elecent said arc to effect the extinction thereof. ment to establish an are, and a monochlorobenzene diazo- 5. A fusible electrical device including a fusible elenium hexailuorophosphate gas-evolving material disposed ment to establish an arc, and a diazonium hexafluorophosadjacent said arc to effect the extinction thereof. phate gas-evolving material disposed adjacent said arc to 5 effect the extinction thereof, References Cited in the le of this patent 6. A fusible electrical device including a fusible element UNITED STATES PATENTS to establish an arc, and a halogenated diazonium hexa- 2 313 580 R ki M 9 1943 fluorophosphate gas-evolving material disposed adjacent an n ar' said arc to eiect the extinction thereof. 10 2539261 Miller Jan' 23 1951 

7. A FUSIBLE ELECTRICAL DEVICE INCLUDING A FUSIBLE ELEMENT TO ESTABLISH AN ARC, AND A MONOCHLOROBENZENE DIAZONIUM HEXAFLUOROPHOSPHATE GASE-EVOLVING MATERIAL DISPOSED ADJACENT SAID ARC TO EFFECT THE EXTINCTION THEREOF. 